
const { Server } = require("socket.io");

const io = new Server({ /* options */ });

const All=function(req,res,next){
    //设置允许跨域的域名，*代表允许任意域名跨域
    res.header("Access-Control-Allow-Origin","*");
    //允许的header类型
    res.header("Access-Control-Allow-Headers","content-type,Authorization");
    //跨域允许的请求方式 
    res.header("Access-Control-Allow-Methods","DELETE,PUT,POST,GET,OPTIONS");
    if (req.method.toLowerCase() == 'options')
    res.sendStatus(200);  //让options尝试请求快速结束
    else
        next();
  }


io.on("connection", (socket) => {
  // ...
  console.log(socket);
  
});

io.listen(3000);